Elongated connecting elements, such as rods, plates, tethers, wires, cables, and other devices have been implanted along the spinal column and connected between two or more anchors engaged between one or more spinal motion segments. Some connecting elements provide a rigid construct that resists movement of the spinal motion segment in response to spinal loading or movement of the spinal motion segment by the patient. Still other connecting elements are flexible to permit at least limited spinal motion while providing resistance to loading and motion of the spinal motion segment. Such flexible connecting elements can be considered to provide dynamic spinal stabilization since at least limited movement of the spinal motion segment is preserved after implantation of the connecting element.
While prior connecting elements provide various spinal stabilization options, there remains a need for connecting elements that can provide dynamic resistance to shear forces and permit motion of the spinal column segment in different directions while maintaining stabilization of the spinal column segment and the structural integrity of the connecting element.